body {
text-align:center;
}


#obalovaci {
position: relative;
width: 800px;
height: 1000px;
margin: auto;
border: 1px rgb(0,0,51) solid;
}

#zahlavi{
background-image: url("o/zahlavi.jpg");
position: absolute;
width:800px;
height:142px;
top: 0px;
left: 0px;
}



<div id=obalovaci>


<div id=zahlavi>
zahlavi
</div></div>